"This thing of rape," said Colonel Edmond Ngarambe, shifting uneasily on his wooden bench high in the mountains of eastern Democratic Republic of Congo, "I can't deny that happens. We are human beings. But it's not just us. The Mai Mai, the government soldiers who are not paid, the Rastas do the same thing. And some people sent by our enemies do it to cause anger against us."

The colonel's words lay bare a brutal reality about the wretched use of rape as an instrument of war in the east of the Congo. The growing numbers of women who arrive daily at hospitals as a fresh bout of fighting engulfs the region often have no idea whether their attackers were from the Mai Mai traditional militia, renegade Tutsi soldiers or a group of deserters from an array of armed groups who wear dreadlocks, call themselves the Rastas and specialise in particularly brutal treatment of their victims.

Ngarambe's own men in the Democratic Forces for the Liberation of Rwanda (FDLR), which evolved out of the army and militia that fled into Congo after leading the 1994 genocide of Rwanda's Tutsis, have been named by human rights groups as among the worst offenders in the onslaught against women, hundreds of thousands of whom have been raped over the past decade of conflict.

Rape has been used to terrorise and punish civilians in Congo who support the "wrong side", and it is perhaps no coincidence that it was also a tool of genocide in the mass murder of the Tutsis. Sexual violence is now so widespread that the medical aid charity, Médecins sans Frontières, says that 75% of all the rape cases it deals with worldwide are in eastern Congo. Darfur is a distant second.

"The two places don't compare," said Augustin Augier, the MSF administrator at Rutshuru hospital, who was previously posted to Darfur. "There you have a lot of people in camps but here the insecurity is so much worse."

The numbers of women seeking treatment for rape at the hospital has risen as a conflict that has already left 4 million dead over the past decade has reignited.

Human rights groups described gang rapes as commonplace and often accompanied by "barbaric" acts of torture with victims beaten with clubs, cut with knives or sexually assaulted with guns. Many young women have been abducted into sexual slavery.

The largest United Nations peacekeeping force in the world of more than 17,000 troops has done little to stop it. Instead, the primary attempt to discourage sexual violence appears on hand-painted murals on walls across the region telling men that it is not manly to rape.

Some of the victims make their way to Rutshuru hospital where they are met by Esparance Kiakimwa, a 29-year-old nurse in its sexual violence unit.

"We treat women and children from many places, sometimes very far. Many others can't get the courage to walk so far so those who arrive often tell us that all the women in the village were raped but they are the only ones to make it to the hospital. The numbers that make it are only a small part of the total," she said.

"They arrive on the back of motorbikes and in cars but sometimes on foot, walking for days because they don't have any money for transport. They have all kinds of injuries like knife cuts and damage to the vagina. It's worse for the young girls. We have to take them immediately to surgery."

Many of the women do not make it to hospital within the 72 hours after the rape in which anti-retroviral drugs to reduce the possibility of contracting HIV are most effective. Four per cent of those who seek treatment are men.

One woman who sought treatment at the hospital tells how she hasn't dared sleep in her own home for months.

"Every woman in the village leaves at night to sleep in the bush because of the raping. They still loot but if they can't find us they can't rape us," she said.

Augier said that women in many villages dare not sleep in their own homes. Others are too afraid even to go to the outskirts of their communities to tend to crops because so many women have been seized in the fields, contributing to the rise in malnutrition and disease that has claimed so many lives.

"People live in fear so they live in the bush. They expose themselves to diseases: malaria, gastro-enteritis. It's cold at night. All of this claims lives," he said.

Human Rights Watch said in a recent report that some armed groups appear to regard rape as a battle tactic aimed at breaking civilian support for rivals or as a means of punishing other ethnic groups.

"In some cases soldiers or combatants raped women and girls as young as five years old as part of a more general attack in which they killed and injured civilians and looted and destroyed property. Their intent was to terrorise communities into accepting their control or to punish them for real or supposed links to opposing forces," it said.

The FDLR is among the primary culprits. But the forces of Laurent Nkunda, a renegade Tutsi general who broke away from the Congolese army to fight the FDLR, have also been accused of systematic rape of Hutu women. So too have the Mai Mai.

Immaculee Birhaheka, head of a women's rights group in Goma, Paif, said those women who make it to hospital are just a fraction of those attacked. She gave as an example what happened in villages along the road south from Goma toward Bukavu. "The women who come from there tell us that every woman in every village has been raped over the years. There is not one who was not attacked they told us," she said.

"Some of them were captured and taken into the forest for months, even two years. When they are released some are in such bad condition that they die."

Brutal attacks

No one has been able to quantify the scale of what human rights groups call the "war on women" in eastern Congo. Tens of thousands of rapes have been recorded by the UN in the eastern provinces of North and South Kivu over the past year, but as only a fraction of the women assaulted make it to hospital there is little doubt that the total number of victims runs into hundreds of thousands in recent years.

In towns such as Shabunda it is estimated that seven out of 10 women have been raped. Many are gang-raped or assaulted over several years. Hospitals have treated girls as young as three. Others have been abducted by armed groups as sex slaves and held in holes in the ground or lashed to trees.

Human rights groups say it is not only the scale of the rape that is significant but the brutality that often accompanies it. Hospitals have treated women who have had guns, sticks and tin cans thrust into their vaginas after being raped. Armed men have also cut babies from the bellies of pregnant women after raping them.

No one group is responsible, and it is not only men in uniform who are committing the assaults. Médecins sans Frontières estimates that about two-thirds of rapes are carried out by combatants with armed groups from the Rwandan Hutu rebels and local Tutsi warlords, Mai Mai traditional militia and the Congolese government army. But many assaults are committed by civilian men, particularly in towns where the rule of law has broken down completely.